The problem of overcrowding at Cora Kelly Magnet School in Alexandria pointed to two obvious solutions: reduce the number of students or increase the amount of classroom space.

Last night the city's School Board voted to do both, despite the protests of some parents and teachers who have argued that the first action would crowd other schools and the second would force some students to work in portable classrooms.

The board voted 7 to 0 for a redistricting plan that would move approximately 175 students from Cora Kelly and agreed to rent three trailers housing two classrooms each. Students entering sixth grade in the fall will have the option of remaining at Cora Kelly, which has special programs in science and computers.

Board member Lynnwood Campbell abstained from voting and Nelson E. Greene Jr. was absent.

Since 1984, when a program stressing science and computer science was established at Cora Kelly, enrollment at the school, which has kindergarten through sixth grade, has swelled from 531 to 636, due largely to growth in the city's Arlandria West section.

"I think we have the spirit back in place. We are determined to make that magnet school come alive again," Superintendent Robert Peebles said before the vote. "It always was alive, but it was crowded."

Magnet schools such as Cora Kelly, at 3600 Commonwealth Ave., are usually established in predominantly minority neighborhoods and outfitted with special programs in arts, sciences or other subjects as "magnets" to draw white students from other areas.

As of April 30, 8 percent of Cora Kelly's students were white, 69 percent were black, 19 percent Hispanic, 4 percent Asian/Pacific Islander and one percent American Indian.

After boundary changes that will result in about 80 former Cora Kelly students going to Mount Vernon elementary and about 45 each to Charles Barrett and Douglas MacArthur elementaries, the remaining student body would be approximately 10 percent white, 77 percent black, 10 percent Hispanic, 3 percent Asian/Pacific Islander and one percent American Indian. The reduction in enrollment and addition of classrooms will open spaces in the school for additional students attracted by the science and computer "magnet."

The trailers cost approximately $17,900 each to rent, install and equip for one year.

Last night Angie Godfrey, president of the Mount Vernon PTA, urged the board to increase resources at the school to educate the additional students who will go there. "You must vote to send staff and services with these children," she said.